Identifying Poisonous Snakes: Here are some guidelines, but there is always some snakes that are exceptions to the rules. For example, not all poisonous snakes have slits for pupils. In the end it does good to still study varieties of poisonous snakes.

Credit: Alamy Of England’s three snake ­species, adders are the most often seen, in forests and on heathland mainly ­in the south-west and north-east. Spot them in early spring when they first emerge from ­hibernation.